JP2024053605A - Keyboard device of keyboard instrument - Google Patents

Abstract

To provide a keyboard device of a keyboard instrument that can prevent noise from being generated at a connection part between a first arm and a second arm of a key support mechanism when a key is pressed and also secure smooth action of the connection part so as to impart an excellent touch feeling.SOLUTION: A keyboard device of a keyboard instrument comprises a keyboard chassis 4, a key 2 which is arranged thereon, and a key support mechanism 6 which supports the key 2 from below and allows the key to act to rotate around virtual fulcra P, Q, wherein a first arm rear-side connection part 37 has a connection shaft 37a extending to the right and left, a second arm front-side connection part 45 has an engagement recessed part 45b which has its side face formed in a U shape to be open to the front and engages with the connection shaft 37a, and the engagement recessed part 45b is fitted with an upper buffer member 51 and a lower buffer member 52 which slide in contact with an outer peripheral surface of an engagement shaft 37a while covering an upper part and a lower part of its inner surface, respectively.SELECTED DRAWING: Figure 8

Description

The present invention relates to a keyboard device for keyboard instruments such as electronic pianos, in which a pressed key rotates around a virtual fulcrum located behind its rear end.

A keyboard device of this type is known from the prior art, for example from Patent Document 1, which has already been filed by the present applicant. This keyboard device is equipped with a key extending in the front-rear direction and a link mechanism that supports the key from below. The link mechanism has a front connecting link bar and a rear connecting link bar that each extend a predetermined length in the front-rear direction, and the front end of the front connecting link bar is rotatably connected to the front part of the key, while the rear end of the rear connecting link bar is rotatably connected to the rear end of the key. In addition, each of the above connecting link bars is rotatably supported via a support pin provided near the center in the length direction, and the rear end of the front connecting link bar and the front end of the rear connecting link bar are rotatably and slidably connected to each other. More specifically, a long hole is formed in the rear end of the front connecting link bar, while a central connecting pin that is inserted into the long hole is protruded from the front end of the rear connecting link bar.

In the keyboard device configured as described above, when the front end of a key is pressed down, each connecting link bar of the link mechanism rotates in a predetermined direction around the support pin. In this case, the central connecting pin of the rear connecting link bar slides along its length while rotating relative to the long hole of the front connecting link bar. When the front end of the key is pressed down to the lowest position, the rear end of the key is positioned approximately half the distance below the front end. This causes the key to rotate around a virtual fulcrum located to the rear, approximately the same length as the key itself. As a result, the key length is shorter than that of an acoustic grand piano, yet the same key operation as that of a grand piano can be obtained.

JP 2020-52391 A (FIGS. 3 to 5)

In the conventional keyboard device described above, each connecting link bar of the link mechanism is made of a hard material such as metal, so depending on the relationship between the diameter of the central connecting pin of the rear connecting link bar and the width dimension of the long hole of the front connecting link bar, there is a risk that the keys cannot be operated properly. In other words, if the diameter of the central connecting pin is smaller than the width dimension of the long hole and a relatively large gap is created between the central connecting pin and the side of the long hole in the width direction, the central connecting pin may hit the side of the long hole when the key is pressed, causing noise. Conversely, if there is almost no gap, the central connecting pin cannot slide smoothly through the long hole, and as a result, the touch when pressing down on the key may feel heavy.

In addition, in the above keyboard device, when a key is pressed down at the back of the key, for example near the center of the key's length, the structure of the link mechanism that supports the key from below can cause the responsiveness of the front connecting link bar to decrease. In that case, a good touch feeling cannot be obtained.

The present invention has been made to solve the above problems, and aims to provide a keyboard device for a keyboard instrument that can prevent noise from occurring at the connection between the first arm and the second arm of the key support mechanism when a key is pressed, while ensuring smooth operation of that connection, thereby providing a good touch feeling.

In order to achieve the above object, the invention according to claim 1 comprises a keyboard chassis, a key extending a predetermined length in the front-rear direction and arranged on the upper part of the keyboard chassis, and a key support mechanism that engages with the keyboard chassis and supports the key from below, and when the key is pressed, causes the pressed key to rotate around a virtual fulcrum located behind the rear end of the key. The key support mechanism is configured to extend a predetermined length in the front-rear direction and engages a first support shaft arranged on the keyboard chassis so as to be able to swing, and includes a first arm whose front end is connected to the front part of the key so as to be able to swing and slide, and a second support shaft arranged on the keyboard chassis so as to extend a predetermined length in the front-rear direction and swings around a second support shaft arranged behind the first support shaft. The second arm has a rear end that is rotatably connected to the rear of the key, and a second arm front connecting part forward of the second pivot that is rotatably and slidably connected to the first arm rear connecting part rear of the first pivot of the first arm. One of the first arm rear connecting part and the second arm front connecting part has an engagement shaft that extends in the left-right direction, and the other of the first arm rear connecting part and the second arm front connecting part has a side shape that is U-shaped opening in one of the front-rear directions and has an engagement recess that engages with the engagement shaft. The engagement recess has an upper cushioning member and a lower cushioning member that slide against the outer circumferential surface of the engagement shaft while covering the upper and lower parts of the inner surface, respectively.

According to this configuration, the key, which extends a predetermined length in the front-rear direction and is arranged on the upper part of the keyboard chassis, is supported from below by the key support mechanism having the first arm and the second arm, and when the key is pressed, it rotates around a virtual fulcrum located behind the rear end of the key. In addition, in the key support mechanism, the first arm rear connecting part of the first arm and the second arm front connecting part of the second arm are connected to each other so as to be freely rotatable and slidable. One of the first arm rear connecting part and the second arm front connecting part has an engagement shaft extending in the left-right direction, and the other has a U-shaped engagement recess whose side shape opens to one side in the front-rear direction. The engagement recess is fitted with an upper buffer member and a lower buffer member that slide against the outer circumferential surface of the engagement shaft while covering the upper and lower parts of the inner surface. In this way, by fitting the upper buffer member and the lower buffer member to the engagement recess, the engagement recess does not directly come into contact with the outer circumferential surface of the engagement shaft, and therefore, when the key is pressed, noise generation at the connection part between the first arm and the second arm of the key support mechanism can be prevented. In addition, the upper and lower cushioning members attached to the engagement recesses slide against the engagement shaft, ensuring smooth operation at the connection between the first and second arms, which provides a good feel when pressing the keys.

The invention according to claim 2 is characterized in that in the keyboard device of the keyboard instrument described in claim 1, the upper cushioning member and the lower cushioning member are configured to have different cushioning properties.

According to this configuration, by configuring the upper and lower cushioning members to have different cushioning properties, it is possible to easily adjust the touch so that a good touch can be obtained regardless of the position of the fingertip when the key is pressed down. In this specification, cushioning properties include the hardness, elasticity coefficient, and/or friction coefficient of the surface that slides against the engagement shaft of the upper and lower cushioning members.

The invention according to claim 3 is characterized in that in the keyboard device of the keyboard instrument described in claim 2, the lower cushioning member is configured to be harder than the upper cushioning member.

With this configuration, the lower cushioning member is harder than the upper cushioning member, so when the back side of the key is pressed down, for example, the first arm responds well, resulting in a satisfying feel when playing the key.

1A and 1B are perspective views showing a portion (for one octave) of a keyboard device of an electronic piano to which the present invention is applied, in which (a) shows the external appearance of the keyboard device and (b) shows a state in which keys other than the white and black keys on the left end are omitted. 2 is a perspective view showing the keyboard device shown in FIG. 1B in a state where the white keys and the black keys, together with their respective key support mechanisms, have been removed from the keyboard chassis; FIG. 1A is a plan view of the keyboard device shown in FIG. 1B, and FIG. 1B is a cross-sectional view taken along line AA. 1A and 1B are perspective views showing a white key and a key support mechanism, in which FIG. 1A shows the white key and the key support mechanism connected together, and FIG. 1B shows the white key and the key support mechanism disassembled. 1A and 1B are perspective views showing a black key and a key support mechanism, in which FIG. 1A shows the black key and the key support mechanism connected together, and FIG. 1B shows the black key and the key support mechanism disassembled. 5A and 5B are diagrams for explaining the operation of a white key in a keyboard device, in which FIG. 5A shows a key-released state and FIG. 5B shows a key-depressed state. 5A and 5B are diagrams for explaining the operation of a black key in a keyboard device, in which FIG. 5A shows a key-released state and FIG. 5B shows a key-depressed state. 1A and 1B are diagrams for explaining the main parts of the present invention, in which (a) is a perspective view showing a white key and its key support mechanism, (b) shows a second arm of the key support mechanism, and (c) shows the second arm with the upper and lower cushioning members removed. 4 is a right side view of the second arm, and an enlarged cross-sectional view of an upper cushioning member and a lower cushioning member. FIG. FIG. 4 is a cross-sectional view similar to FIG. 3(b), showing a state in which the upper and lower cushioning members are attached to the second arm. 1A and 1B are diagrams for explaining the forces acting on the key and the second arm depending on the position of the key pressed when the key is pressed, where (a) shows the case where the front end of the key is pressed down, and (b) shows the case where the back side of the key is pressed down. 11 is a perspective view illustrating a lower cushioning member configured to have different cushioning properties from an upper cushioning member; FIG.

A preferred embodiment of the present invention will now be described in detail with reference to the drawings. FIG. 1(a) shows only one octave of the keyboard device 1 of an electronic piano to which the present invention is applied. In the following explanation, the basic structure and operation of the keyboard device 1 will first be explained, and then the main parts of the present invention will be explained.

Figure 1(b) shows the keyboard device 1 of Figure 1(a) with all keys 2 omitted except for the white key 2a and black key 2b on the left end, and Figure 2 shows the white key 2a and black key 2b removed from the keyboard chassis 4 together with the key support mechanism 6.

This keyboard device 1 is equipped with a keyboard chassis 4, a number of keys 2 consisting of white keys 2a and black keys 2b arranged in a row in the left-right direction, a key support mechanism 6 that is rotatably attached to the keyboard chassis 4 for each key 2 and supports the corresponding key 2 from below, and a key switch 3 for detecting key press information for each key 2.

The keyboard chassis 4 has a chassis body 4a made of a resin molded product of a predetermined shape, for example, by injection molding a predetermined resin material (e.g., ABS resin). As shown in FIG. 3, the front part 11, middle part 12, and rear part 13 of the chassis body 4a are all formed to extend in the left-right direction as a whole (left-right direction in FIG. 3(a)), and are integrally molded with a plurality of ribs 14 spaced apart in the left-right direction and each extending in the front-rear direction. In the following description, the front part 11, middle part 12, and rear part 13 of the chassis body 4a of the keyboard chassis 4 will be referred to as the "chassis front part 11," the "chassis middle part 12," and the "chassis rear part 13," respectively.

The chassis front 11 is mainly for guiding the white key 2a when the key is pressed, and for regulating the upper and lower limit positions of the front end of the white key 2a. A plurality of white key guides 11a are arranged in a left-right direction and are inserted from below into the chassis front 11 for each white key 2a to prevent the white key 2a from swaying sideways. The chassis front 11 also has engagement holes 11b, 11b that penetrate in the vertical direction on both the left and right sides of each white key guide 11a, and the two upper limit position regulating parts 21, 21 of the white key 2a, which will be described later, engage with the engagement holes 11b, 11b, respectively. Furthermore, the chassis front 11 has a stopper attachment part 11c at its front end that protrudes forward and extends in the left-right direction over the entire chassis body 4a, and a key upper limit stopper 16a and a key lower limit stopper 16b for the white key are attached to the lower and upper surfaces of the stopper attachment part 11c, respectively, so as to extend in the left-right direction. In addition, a black key stopper attachment section 11d is provided on the chassis front section 11 at a specified position behind the white key guide 11a, and extends left and right across the entire chassis body 4a. An upper key limit stopper 17 for the black keys is attached to this stopper attachment section 11d so as to extend left and right.

The chassis intermediate section 12 mainly guides the black key 2b when the key is pressed, and also supports the first arm 31 and the second arm 32 of the key support mechanism 6a, 6b for the white and black keys so that they can swing freely. The chassis intermediate section 12 has a flat plate-like flat section 12a extending in the left-right direction, and a plurality of black key guides 12b standing on the flat section 12a and spaced appropriately in the left-right direction. Each black key guide 12b is inserted from below for each black key 2b to prevent the black key 2b from swinging sideways. In addition, a first arm support section 18 that supports the first arm 31 of the key support mechanism 6 is provided at the front of the chassis intermediate section 12. The first arm support section 18 has a plurality of first support shafts 18a that are provided between adjacent ribs 14, 14 so as to extend in the left-right direction, and the first arm 31 is supported by these first support shafts 18a so that it can swing freely. Furthermore, a second arm support 19 is provided at the rear of the chassis intermediate section 12 to support the second arm 32 of the key support mechanism 6. The second arm support 19 has a plurality of second support shafts 19a provided between adjacent ribs 14, 14 to extend in the left-right direction. The second support shafts 19a are arranged on the same axis extending in the left-right direction at a position rearward and higher than the first support shaft 18a, and the second arm 32 is supported by these second support shafts 19a so as to be able to swing freely. In addition, a first arm lower limit stopper 10b extending in the left-right direction over the entire chassis main body 4a is provided at a predetermined position of a middle rail 8 (described later) provided on the lower side of the chassis intermediate section 12.

The key switch 3 is attached to the bottom of the keyboard chassis 4, between the chassis front part 11 and the chassis middle part 12. The key switch 3 is composed of a horizontally elongated printed circuit board 3a extending in the left-right direction, and multiple switch bodies 3b made of rubber switches attached to the printed circuit board 3a for each key 2 and pressed by the first arm 31 when the key is pressed.

The chassis rear part 13 mainly guides the key 2 in the vertical direction while preventing lateral vibration at its rear end, and regulates the upper limit position of the rear end of the first arm 31. As shown in Figures 2 and 3(a), the chassis rear part 13 has a plurality of partition walls 13a spaced apart from each other at a predetermined interval in the left-right direction to separate adjacent keys 2, 2. Also, as shown in Figure 3(b), a first arm upper limit stopper 10a extending in the left-right direction over the entire chassis main body 4a is provided at a predetermined position on the upper part of the chassis rear part 13. This first arm upper limit stopper 10a and the first arm lower limit stopper 10b provided on the chassis intermediate part 12 are intended to regulate the upper limit position of the first arm 31, which functions as a hammer for applying touch weight to the key 2, when the first arm 31 rotates upward and the lower limit position when the first arm 31 rotates downward. In addition, a metal cover plate 15 is attached to the top of the rear part 13 of the chassis, extending left and right across the entire chassis body 4a and positioned to cover the rear end of the key 2.

As shown in Figs. 2 and 3(a), the chassis body 4a of the keyboard chassis 4 configured as described above has a plurality of first openings 5a that open upward and forward, and a plurality of second openings 5b that open upward. Through each of the first openings 5a, the first arm 31 of the key support mechanism 6 engages with the first support shaft 18a from the outside, and through each of the second openings 5b, the second arm 32 engages with the second support shaft 19a from the outside.

In addition, in the keyboard chassis 4, multiple chassis bodies 4a are connected to each other in a line in the left-right direction, and are screwed in a state in which they are placed on metal front rails 7, middle rails 8, and rear rails 9 that all extend in the left-right direction and are arranged at a predetermined distance from each other in the front-to-rear direction. The keyboard chassis 4 is then fixed to a shelf board (not shown) of the electronic piano via the front rails 7 and rear rails 9.

Next, the key 2 and the key support mechanism 6 will be described. FIG. 4(a) shows an enlarged view of the white key 2a and its key support mechanism 6a, and FIG. 4(b) shows them exploded. As shown in the figure, the white key 2a is formed by injection molding a specific resin material (e.g., AS resin) to extend a specific length in the front-rear direction and to be hollow and open downward. The front end of the white key 2a is provided with a pair of left and right upper limit position restricting parts 21, 21 that extend downward from the left and right side walls and are formed so that their lower ends are bent forward. As described above, these upper limit position restricting parts 21, 21 engage with the left and right engagement holes 11b, 11b of the chassis front part 11 while penetrating them, respectively.

The front of the white key 2a is provided with a key front connector 22, which is connected to the first arm 31 of the key support mechanism 6a, at a predetermined position behind the upper limit regulating part 21. The key front connector 22 has a U-shaped connector recess 22a with an elongated hole-like side and an open front. The connector recess 22a is fitted with a buffer member 20, which covers the entire inner periphery of the connector recess 22a and suppresses noise generation when the connector shaft 35b of the first arm 31 slides within the connector recess 22a. A keyboard weight 30 (see FIG. 3) is fitted to the front of the white key 2a between the upper limit regulating part 21 and the key front connector 22 to provide a desired touch weight when the key is pressed.

Furthermore, the rear of the white key 2a is provided with a key rear connecting part 23 that is connected to the second arm 32 of the key support mechanism 6a. This key rear connecting part 23 has a plate-shaped connecting body part 23a that hangs down from the center of the white key 2a in the left-right direction and has a predetermined thickness in the left-right direction, and a pair of left and right engagement protrusions 23b, 23b that protrude coaxially from the left and right side surfaces of the connecting body part 23a. In addition, a tool insertion hole 24 is formed in the rear of the white key 2a, which penetrates in the up-down direction and is used to insert a specific tool from above when releasing the connection between the white key 2a and the second arm 32 of the key support mechanism 6a during maintenance of the keyboard device 1, etc.

On the other hand, the key support mechanism 6a has a first arm 31 and a second arm 32 that engage with each other and are connected to the front key connecting portion 22 and the rear key connecting portion 23 of the white key 2a, respectively.

As shown in FIG. 4(b), the first arm 31 is composed of an arm body 33 and two weights 34, 34 attached to the arm body 33. The arm body 33 is composed of a resin molded product of a predetermined shape, such as by injection molding a predetermined resin material (e.g., polyacetal). The arm body 33 extends a predetermined length in the front-rear direction, and at its front end is provided a first arm front connecting part 35 that connects to the key front connecting part 22 of the white key 2a. The first arm front connecting part 35 has a box part 35a formed in a box shape that opens upward and forward, and a connecting shaft 35b that is provided to extend in the left-right direction while connecting the front upper ends of the left and right side walls of the box part 35a. The connecting shaft 35b is connected to the connecting recess 22a of the key front connecting part 22 of the white key 2a so as to be freely rotatable and freely slidable in the front-rear direction.

The arm body 33 also has a U-shaped bearing 36 with a downwardly open side at a predetermined position immediately behind the first arm front connecting portion 35, and this bearing 36 rotatably engages with the first support shaft 18a of the keyboard chassis 4. Furthermore, the arm body 33 has a first arm rear connecting portion 37 that connects to the second arm 32 at a predetermined position behind the bearing 36. Specifically, the first arm rear connecting portion 37 has a connecting shaft 37a that extends in the left-right direction and has both ends that protrude outward from the left and right sides of the arm body 33. Both ends of this connecting shaft 37a engage with connecting recesses 45b, 45b of the second arm front connecting portion 45 of the second arm 32, which will be described later.

Two elongated plate-like weights 34, 34 are attached to the weight attachment section 38 at the rear of the arm body 33, sandwiching the weight attachment section 38 from both sides. Each weight 34 is made of a material (e.g., a metal such as iron) with a higher specific gravity than the arm body 33, and is formed into a predetermined shape by pressing a metal plate, etc.

The second arm 32 is made of a resin molded product of a predetermined shape by injection molding the same resin material as the arm body 33 of the first arm 31. This second arm 32 is shorter than the first arm 31 and extends a predetermined length in the front-to-rear direction. In addition, the second arm 32 has a C-shaped bearing portion 41 near the center in the longitudinal direction, with the side shape opening forward, and this bearing portion 41 rotatably engages with the second support shaft 19a in the keyboard chassis 4.

The rear of the second arm 32 is provided with a second arm rear connecting part 42 that is connected to the key rear connecting part 23 of the white key 2a. This second arm rear connecting part 42 is bifurcated and has two connecting arms 43, 43 that extend parallel to each other for a predetermined length along the length of the second arm 32. A connecting hole 43a that penetrates in the left-right direction is formed at the rear end of each connecting arm 43. Between their rear ends, the connecting arms 43, 43 hold the connecting body part 23a of the key rear connecting part 23 of the white key 2a from both the left and right sides, and each connecting hole 43a fits rotatably into the corresponding engaging protrusion 23b of the key rear connecting part 23.

Furthermore, a second arm front connecting part 45 is provided at the front of the second arm 32, which is connected to the first arm rear connecting part 37 of the first arm 31. This second arm front connecting part 45 has a pair of left and right connecting pieces 45a, 45a spaced a predetermined distance from each other in the left-right direction, and each connecting piece 45a has a U-shaped connecting recess 45b whose side shape is an elongated hole and opens forward. The left and right connecting pieces 45a, 45a of the second arm front connecting part 45 are rotatably and slidably engaged with both ends of the connecting shaft 37a of the first arm 31 via the connecting recesses 45b, 45b.

5(a) shows the black key 2b and its key support mechanism 6b in an enlarged view, and FIG. 5(b) shows them in an exploded view. The black key 2b is formed by injection molding the same resin material as the white key 2a, and is shorter than the white key 2a, extends a predetermined length in the front-rear direction, and is hollow and open downward. The front lower end of the black key 2b is provided with a front-side connecting part 26 formed in a manner similar to the front-side connecting part 22 of the white key 2a. This front-side connecting part 26 has a connecting recess 26a whose side shape is an elongated hole and is formed in a U-shape that opens forward. In addition, the front-side connecting part 26 has an extension part 26b at the lower front end of the connecting recess 26a, which extends a predetermined length forward from the front surface of the main body of the black key 2b, and this extension part 26b functions as an upper limit position regulating part for the black key 2b. In the following explanation, the same components of the black key 2b and key support mechanism 6b as those of the white key 2a and key support mechanism 6a described above will be given the same reference numerals and detailed explanations will be omitted.

The key support mechanism 6b that supports the black key 2b is constructed in a manner similar to the key support mechanism 6a for white keys described above. Specifically, the arm body 33 of the first arm 31 and the second arm 32 of the key support mechanism 6b are constructed to be exactly the same shape and size as the arm body 33 and the second arm 32 of the key support mechanism 6a for white keys. Note that the two weights 34, 34 on the left and right of the key support mechanism 6b for black keys are illustrated as being the same as the weights 34, 34 of the key support mechanism 6b for white keys, but the shape and length are appropriately changed depending on the touch weight required for the key 2, etc.

Next, the operation of the keys 2 and the key support mechanism 6 in the keyboard device 1 configured as described above will be described. Figure 6 shows the operation of the white key 2a and its key support mechanism 6a, and Figure 7 shows the operation of the black key 2b and its key support mechanism 6b.

When the front end of the white key 2a is pressed down by the player's finger in the released key state shown in FIG. 6(a), the front key connection part 22 of the white key 2a moves downward, causing the first arm 31 to rotate counterclockwise around the first support shaft 18a. In addition, with the rotation of the first arm 31, the front second arm connection part 45, which engages with the connection shaft 37a of the first arm 31 via the connection recess 45b, moves upward. As a result, the second arm 32 rotates clockwise around the second support shaft 19a. With the rotation of the second arm 32, the rear key connection part 23 connected via the rear second arm connection part 42 at the rear end is pulled down, and the rear end of the white key 2a moves downward.

When the first arm 31 rotates as described above, the box portion 35a of the first arm front connecting portion 35 moves downward, and the bottom wall of the box portion 35a presses the switch body 3b of the key switch 3 corresponding to the pressed key 2 from above. As a result, the electronic piano detects the key press information of the pressed key 2, and a sound is generated from a speaker (not shown) based on the detected key press information.

When the white key 2a is pressed down as described above, as the first arm 31 rotates counterclockwise, the weight 34 of the first arm 31 tilts upward at the rear as shown in FIG. 6(b), and the rear end abuts against the first arm upper limit stopper 10a from below. This prevents the first arm 31 from rotating any further. Then, when the front end of the white key 2a is pressed down to the lowest position, the front end of the white key 2a abuts against the key lower limit stopper 16b, preventing the white key 2a from being pressed down any further.

When the white key 2a is pressed as described above, it rotates around the virtual fulcrum P, which is located behind its rear end. The position of this virtual fulcrum P is set, for example, so that the distance from the front end of the white key 2a is approximately twice the length of the white key 2a itself. As a result, when the front end of the white key 2a is pressed down to the lowest position, the front end of the white key 2a is located a predetermined key stroke (e.g., 10 mm) lower, and the rear end is located approximately half the distance of the key stroke (e.g., 5 mm) lower, compared to when the key is released as shown in FIG. 6(a).

On the other hand, when the pressed white key 2a is released, the weight of the weight 34 causes the first arm 31 of the key support mechanism 6a to rotate in the opposite direction to the above, and the second arm 32 also rotates in the opposite direction to the above. As a result, the white key 2a rotates upward around the virtual fulcrum P. Then, a specific portion of the first arm 31 behind the first support shaft 18a abuts against the first arm lower limit stopper 10b from above, and both upper limit position regulating parts 21, 21 of the white key 2a abut against the key upper limit stopper 16a from below, preventing further rotation of the white key 2a and returning it to its original released state.

The operation of the black key 2b when it is pressed is the same as that of the white key 2a and the key support mechanism 6a described above. That is, when the front end of the black key 2b is pressed down in the key-released state shown in FIG. 7(a), the first arm 31 rotates counterclockwise around the first support shaft 18a, and the second arm 32 rotates clockwise around the second support shaft 19a, so that the black key 2b rotates around the virtual fulcrum Q at the rear. The position of this virtual fulcrum Q is set so that the distance from the front end of the black key 2b is about twice the length of the black key 2 itself, for example, like the virtual fulcrum P of the white key 2a described above. Therefore, when the front end of the black key 2b is pressed down to the lowest position, the front end of the black key 2b is located lower by a predetermined key stroke, and the rear end is located lower by about 1/2 the distance of the key stroke, compared to when the key is released as shown in FIG. 7(a).

On the other hand, when the pressed black key 2b is released, the first arm 31 and the second arm 32 of the key support mechanism 6b rotate in the opposite direction, causing the black key 2b to rotate upward around the virtual fulcrum Q. Then, the extension 26b of the front-key connecting part 26 of the black key 2b abuts against the upper key stopper 17 from below, preventing further rotation of the black key 2b and returning it to its original released state.

Next, the main part of the present invention will be described with reference to Figures 8 to 11. The main part of the present invention is that the second arm 32 of the key support mechanism 6 is provided with an upper buffer member 51 and a lower buffer member 52 in sliding contact with the connecting shaft 37a (engagement shaft) of the first arm 31 at the second arm front connecting part 45, which is the connecting part with the first arm 31.

Figure 8 (a) shows the white key 2a and its key support mechanism 6a, (b) shows the second arm 32 of the key support mechanism 6a, and (c) shows the second arm 32 with the upper cushioning member 51 and lower cushioning member 52 removed.

Both the upper cushioning member 51 and the lower cushioning member 52 are made of molded parts made of a specific synthetic resin (e.g., thermoplastic elastomer) that has elasticity.

As shown in FIG. 8(c), the upper cushioning member 51 has two angular tubes 51a, 51a extending a predetermined length in the front-rear direction, a connecting portion 51b connecting the rear ends of the upper surfaces of the two angular tubes 51a, 51a, and a locking portion 51c protruding rearward from the rear end of each angular tube 51a. The upper cushioning member 51 is attached to the second arm front connecting portion 45 with the upper protruding upper protrusions 45U, 45U of the left and right connecting pieces 45a, 45a of the second arm front connecting portion 45 inserted into the two angular tubes 51a, 51a, respectively, and with each locking portion 51c locked to the rear upper portion of the second arm front connecting portion 45. As a result, the upper cushioning member 51 is firmly attached to the second arm front connecting portion 45 with the upper inner surfaces of the connecting recesses 45b, 45b of the left and right connecting pieces 45a, 45a covered.

On the other hand, the lower cushioning member 52 is constructed in a manner similar to the upper cushioning member 51 described above, and has two angular tubes 52a, 52a extending a predetermined length in the front-rear direction, a connecting portion 52b connecting the rear ends of the two angular tubes 52a, 52a, and a locking portion 52c extending a predetermined length rearward from the rear end of each angular tube 52a. This lower cushioning member 52 is attached to the second arm front connecting portion 45 with the lower protruding portions 45D, 45D of the left and right connecting pieces 45a, 45a of the second arm front connecting portion 45 inserted into the two angular tubes 52a, 52a, respectively, and with each locking portion 52c locked to the rear lower portion of the second arm front connecting portion 45. As a result, the lower cushioning member 52 is firmly attached to the second arm front connecting part 45 while covering the lower parts of the inner surfaces of the connecting recesses 45b, 45b of the left and right connecting pieces 45a, 45a.

Figure 9 shows a right side view of the second arm 32 to which the upper and lower cushioning members 51 and 52 are attached, and also shows an enlarged cross section of both cushioning members 51 and 52. As shown in the figure, in the second arm front connecting part 45 to which both cushioning members 51 and 52 are attached, the lower surface of the square tube portion 51a of the upper cushioning member 51 slides against the connecting shaft 37a in the first arm rear connecting part 37 of the first arm 31, and the upper surface of the square tube portion 52a of the lower cushioning member 52 slides against the connecting shaft 37a in the first arm rear connecting part 37 of the first arm 31. In the following description, the lower surface of each square tube portion 51a of the upper cushioning member 51 will be referred to as the "lower sliding surface 51d" as appropriate, and the upper surface of each square tube portion 52a of the lower cushioning member 52 will be referred to as the "upper sliding surface 52d" as appropriate.

Figure 10 is a diagram of the keyboard device 1 similar to that of Figure 3(b) described above, showing the state in which the upper and lower cushioning members 51 and 52 described above are attached to the second arm front connecting portion 45 of the second arm 32. Figure 11 shows the forces acting on the key 2 and the second arm 32 when the keyboard device 1 shown in Figure 10 is used and the key 2 is pressed at different positions.

As shown in FIG. 11(a), when the front end of the key 2 is pushed down (see black arrow), the connecting shaft 35b, which is the connecting part with the first arm 31, functions as a fulcrum, and the rear end of the key 2 tries to rotate upward (see arc-shaped white arrow). Accordingly, the second arm 32, which is connected to the rear end of the key 2 via the engagement protrusion 23b, is subjected to a force that rotates the second arm 32 counterclockwise in FIG. 11(a) around the second support shaft 19a (see white arrow at the rear end of the second arm 32). In this case, in the second arm 32, the lower sliding surface 51d of the upper buffer member 51 of the upper buffer member 51 and the lower buffer member 52 attached to the second arm front connecting part 45 is strongly pressed against the connecting shaft 37a, which is the connecting part with the first arm 31 (see white arrow at the front end of the second arm 32), and the connecting shaft 37a slides toward the back of the connecting recess 45b.

On the other hand, as shown in FIG. 11(b), when the back side of the key 2 is pushed down (see black arrow), the above-mentioned connecting shaft 35b functions as a fulcrum, and the rear end of the key 2 tries to rotate downward (see arc-shaped white arrow). Accordingly, a force acts on the second arm 32 connected to the rear end of the key 2 to rotate it clockwise in FIG. 11(b) around the second support shaft 19a (see the white arrow at the rear end of the second arm 32). In this case, unlike the case of FIG. 11(a) described above, in the second arm 32, the upper sliding surface 52d of the lower cushioning member 52 is strongly pressed against the connecting shaft 37a of the first arm 31 (see the white arrow at the front end of the second arm 32), and the connecting shaft 37a slides toward the back side of the connecting recess 45b.

The difference in the depressed position of the key 2 described above can cause the following problems. That is, as shown in FIG. 11(a), when the front end of the key 2 is depressed, the first arm 31 rotates with good responsiveness. However, as shown in FIG. 11(b), when the back side of the key 2 is depressed, the responsiveness of the first arm 31 decreases, and the desired touch feeling may not be obtained. One of the reasons for this is thought to be that the cushioning properties of the upper cushioning member 51 and lower cushioning member 52 attached to the second arm 32 are the same.

The upper and lower cushioning members 51 and 52 are configured to have different cushioning properties, thereby adjusting the touch when the back side of the key 2 is pressed down. For example, by configuring the lower cushioning member 52 from a harder material than the upper cushioning member 51, it is possible to obtain a good operational response of the first arm 31 when the back side of the key 2 is pressed down, resulting in a responsive touch.

As described above, according to the keyboard device 1 to which the essential parts of the present invention are applied, the upper and lower cushioning members 51 and 52 that cover the upper and lower parts of the inner surface of the connecting recess 45b are attached to the second arm front connecting portion 45 of the second arm 32, and the connecting shaft 37a of the first arm 31 slides against the lower sliding surface 51d of the upper cushioning member 51 and the upper sliding surface 52d of the lower cushioning member 52. This prevents the connecting shaft 37a of the first arm 31 from directly hitting the inner surface of the connecting recess 45b of the second arm 32, and therefore prevents noise from being generated at the connecting portion between the first arm 31 and the second arm 32 of the key support mechanism 6 when a key is pressed. In addition, smooth operation can be ensured at the connecting portion between the first arm 31 and the second arm 32, which provides a good touch when a key is pressed.

Also, as mentioned above, by configuring the upper and lower cushioning members 51 and 52 to have different cushioning properties, it is possible to adjust the touch sensation when the back side of the key 2 is pressed down.

Figure 12 illustrates a lower buffer member 52 configured to have different buffer properties compared to the upper buffer member 51. In the lower buffer member 52A shown in Figure 12(a), two grooves 61, 61 extending over the entire length of the upper surface of each square tube portion 52a are formed. In the lower buffer member 52B shown in Figure 12(b), a number of protrusions 62 are formed on the upper surface of each square tube portion 52a. Furthermore, in the lower buffer member 52C shown in Figure 12(c), two grooves 63, 63 extending over the entire length of the inner ceiling surface of each square tube portion 52a are formed. By configuring the lower buffer member 52 in this way, it is relatively easy to obtain a lower buffer member 52 with different buffer properties compared to the upper buffer member 51, even if the lower buffer member 52 is made of the same material as the upper buffer member 51.

Note that the detailed configurations of the keyboard device 1, the key 2, the key support mechanism 6, the upper cushioning member 51, and the lower cushioning member 52 shown in the embodiment are merely examples and can be modified as appropriate within the scope of the spirit of the present invention.

REFERENCE SIGNS LIST 1 Keyboard device 2 Key 2a White key 2b Black key 4 Keyboard chassis 4a Chassis body 6 Key support mechanism 6a Key support mechanism for white keys 6b Key support mechanism for black keys 18a First support shaft 19a Second support shaft 31 First arm 32 Second arm 37 First arm rear connecting portion 37a Connecting shaft (engagement shaft)
45 Second arm front connecting portion 45a Connecting piece 45b Connecting recess 45U Upper protruding portion 45D Lower protruding portion 51 Upper buffer member 51a Square tube portion 51d Lower sliding surface 52 Lower buffer member 52a Square tube portion 52d Upper sliding surface

Claims (3)

A keyboard chassis and
A key extending a predetermined length in the front-rear direction and disposed on the upper part of the keyboard chassis;
a key support mechanism that is engaged with the keyboard chassis and supports the key from below, and that, when a key is pressed, causes the pressed key to rotate about a virtual fulcrum that is located behind the rear end of the key;
Equipped with
The key support mechanism includes:
a first arm configured to extend a predetermined length in the front-rear direction, pivotably engaged with a first support shaft provided on the keyboard chassis, and a front end of which is rotatably and slidably connected to a front portion of the key;
a second arm configured to extend a predetermined length in the front-rear direction, pivotally engaging with a second support shaft provided on the keyboard chassis rearward of the first support shaft, with a rear end rotatably connected to the rear of the key, and a second arm front connector forward of the second support shaft rotatably and slidably connected to a first arm rear connector rearward of the first support shaft of the first arm;
It has
one of the first arm rear connecting portion and the second arm front connecting portion has an engagement shaft extending in the left-right direction,
the other of the first arm rear connecting portion and the second arm front connecting portion has a U-shaped side shape that is open to one side in a front-rear direction and has an engagement recess that engages with the engagement shaft,
A keyboard device for a keyboard instrument, characterized in that an upper cushioning member and a lower cushioning member are attached to the engagement recess, covering the upper and lower parts of the inner surface of the engagement recess, respectively, and making sliding contact with the outer circumferential surface of the engagement shaft. The keyboard device of a keyboard instrument according to claim 1, characterized in that the upper and lower cushioning members are configured to have different cushioning properties. 3. The keyboard device for a keyboard instrument according to claim 2, wherein the lower cushioning member is harder than the upper cushioning member.

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